This invention relates to electrostimulation devices and particularly, but not exclusively to microcurrent electrostimulation devices that are suitable for applying currents in the order of 10−6 amperes to the skin and underlying muscle of a user.
Previously proposed electrostimulation devices have tended to be of one of two types—microcurrent devices that are configured to apply currents in the order of 10−6 amperes to the skin and underlying muscle of a user and millicurrent devices that are configured to apply larger currents of in the order of 10−3 amperes to the skin and underlying muscles of a user.
In general terms, millicurrent devices are designed to stimulate muscle tissue and improve muscle tone by virtue of a process known as “passive gymnastics” where a current applied to the skin and underlying muscle of a subject causes an involuntary rhythmic contraction of the muscles that improves muscle tone. Microcurrent devices are configured to apply much smaller currents. Treatments with a microcurrent device do not cause muscle contraction and tend to be barely detectable by the subject.
Microcurrent treatments have been shown to increase the amount of ATP (adenosine triphosphate) within the cells of a muscle. For example, a study by Ngok Cheng, M.D. et al (“The Effects of Electric Currents on ATP Generation, Protein Synthesis, and Membrane Transport in Rat Skin,” Clinical Orthopaedics and Related Research, No. 171, November-December 1982, pp. 264-271) showed that the application of a current of in the order of 50 to 500 microamperes to the skin and underlying muscle of a subject causes an increase in mitochondria and protein synthesis in the muscle, an increase in aminoisobutyric acid uptake, an increase in protein synthesis and Gluconeogenesis (biosynthesis of new glucose) and a 300-500% increase in ATP (Adenosine triphosphate) levels.
These dramatic increases in cellular ATP levels have been shown to help muscles retain a re-educated form for longer periods of time, and as a consequence such techniques are of use in muscle toning treatments. However, for these benefits to be appreciable it is necessary to for the muscle to be manipulated (for example by extending or compressing the muscle) whilst the treatment is taking place. In a salon environment this is relatively easy to accomplish as microcurrent electrostimulation devices typically comprise a pair of probes that can be used by a technician during a treatment to manipulate the skin and muscle so that the muscle is forced into a desired form for re-education. This contrasts with the home environment where subjects typically apply microcurrent treatments to themselves without the assistance of another person.
One previously proposed microcurrent electrostimulation device that is intended for personal rather than commercial use is the Rio® facial rejuvenator device offered for sale by The Dezac Group Ltd. This device is similar to commercial devices in that it comprises a pair of wands with conducting tips that can be used to squeeze the skin and underlying muscle whilst a microcurrent is applied thereto. Whilst this device does allow a subject to manipulate their skin and underlying muscle in the course of a muscle toning electrostimulation treatment, a problem with the device is that the subject needs to look in a mirror to be able to locate the wands on the skin and squeeze or lengthen the correct muscle.
Another previously proposed electrostimulation device is the NuFace® device from the Carol Cole Company (see WO2006/116728). This device comprises a hand-holdable housing from which a pair of electrodes project and circuitry for establishing a potential difference between the electrodes so that a microcurrent flows between the electrodes when the electrodes are placed on the skin.
A drawback with the NuFace® device is that as it can only be used in a manner in which the electrodes are brushed over the skin. It cannot be used for muscle toning treatments where the skin and muscle are manipulated whilst the current is applied. As aforementioned, for electrostimulation treatments that are designed to re-educate muscles (for example a cosmetic treatment to reduce the severity of wrinkles) it is preferred that the muscle be manipulated (for example squeezed or lengthened) whilst the treatment is undertaken so that the increased cellular levels of ATP can retain the muscle in its re-educated form for longer.
Another previously proposed device is the Tua Viso electrostimulation device from Vupiesse Italia (see EP 0603 451). This device is similar in concept to the NuFace® device and is used in the same way by brushing the electrodes over the surface of the skin to be treated. As a consequence, the Tua Viso device suffers from the same drawbacks as the NuFace® device. A further problem is that whilst the Tua Viso device is described as being a microcurrent device, tests have indicated that it actually applies a current that is closer to that a millicurrent device would produce.
Since research has shown that the application of a current of 600 micro amps or more can actually reduce cellular ATP levels, the Tua Viso device would not be suitable for enhancing retention of re-educated muscle form in the manner aforementioned. Also the application of currents of this magnitude to delicate facial muscles can be uncomfortable, and that the characteristic muscle contractions associated with these higher current devices can actually worsen the appearance of lines and wrinkles in some areas of the face.
Iontophoresis is a known process in which charged particles are propelled, non-invasively, through the dermis of a subject by means of a repulsive electromotive force that results from the application of an electric field to a similarly charged particle (such as the particles of a medicament or a cosmetic treatment). The applied electric field pushes the particles deeper into the skin to achieve a better therapeutic or cosmetic effect.
In the context of electrostimulation devices it has previously been proposed to provide electrolytic fluids that function to improve current flow to the skin of the subject, and for these fluids to have a cosmetic or therapeutic effect. For example, in the context of the NuFace® device, it has been proposed to provide a conductivity gel that is smeared over the subject's face prior to use of the device, and an optimizing mist that can be sprayed onto the gel to keep the gel moist during a NuFace® treatment. Smearing a subject's face with gel is necessarily quite messy and it is difficult to ensure that the gel is exactly where it is needed. Also cleaning the device after use can be problematic.
The Tua Viso device has chambers that are associated with each of the electrodes, and which can be filled with fluid or fluid-filled cartridges that are sealed with a breakable membrane. It is known to cover each of the electrodes of the Tua Viso device with a “spongey material” that is humidified by the fluid to keep the skin dampened during use of the device. Whilst this arrangement is better than that proposed for the NuFace® device, the electrode assemblies of the Tua Viso device still need to be disassembled to be properly cleaned after use. The sponges can also be difficult to put on and take off, and that the need to purchase replacement cartridges and sponges can substantially increase the cost of using of the device.